Tim and Nina Zagat, who founded the now-famous Zagat guides over dinner with friends one evening in 1979, had no idea they'd be publishing those handy, pocket-sized paperbacks during a restaurant revolution. Today, as more people than ever eat out, the diversity of cuisines is exploding, and chefs are celebrities, those burgundy-colored Zagat guides are a hot item. They are to American restaurateurs what the emerald-green Michelin guides have long been to tourists in Europe.

It's no wonder these former lawyers who turned their hobby into a successful enterprise have recently branched out, launching guides to hotels, nightlife, movies, music, shopping, family travel, spas, and golf courses. But the restaurant guides – which are written by and for consumers with a 30-point rating system in the categories of food, décor, service, and cost – remain the Zagats' best-known product and perhaps also, their favorite "firstborn."

On a recent spring day in Boston, a Monitor reporter-and-photographer team took shelter from torrential rain with the Zagats at Bin 26 Enoteca, one of the top-rated "newcomer" restaurants in their latest Boston guide. The couple was in town from New York to launch the Boston guide, the first in the US to be unveiled with a revised, more user-friendly format. While Tim tackled his Hangar Steak "Tagliata" and Nina nibbled on her Grilled Vegetables With Roasted Mozzarella, they shared their keen trend-spotting insights.

"Italian food is as popular as ever," says Tim, "but who knew, 10 years ago, anything about sushi or soba bars?" Japanese cuisine has soared in popularity, he adds, explaining that this year it took the fourth spot in their poll, with 11 percent of Americans citing Japanese as their favorite cuisine, just behind the 14 percent who declared French as their favorite. (Italian took first with 27 percent and American tied with French at 14 percent.)

Other Asian cuisines, especially Thai, Vietnamese, and those of lesser-known regions of China, such as Mongolian cooking, have also gained popularity in recent years, he says, adding that the more familiar, or "regular" Chinese food, has gotten worse – at least in US restaurants.

It's another story in China, where the food in those well-known regions is better than ever, say the Zagats, who travel abroad six to eight times per year. Shanghai and Beijing are two of their favorite foreign cities. "There's been the most amazing transformation in Shanghai, especially," says Nina. Other places they love to visit are London, Paris, Milan, and the Parma region of Italy.

America's melting-pot cuisine

Living in New York, a city with its endless variety in ethnic cuisines, they often feel as though they can travel just by walking down the street. This isn't anything new in the Big Apple. But now smaller US cities are also bursting with culinary diversity. These days, in almost any American city, one might find a burger joint, a Spanish tapas bar, a French-Cambodian cafe, an Italian trattoria, and a Mexican taqueria all in the same neighborhood.

"The quality and diversity of cuisine in American cities is astonishing," says Tim. For example, he adds, when they published their first Boston guide 18 years ago, there were about 20 different types of cuisine available; today, there are 80. In that first guide, surveyors rated and reviewed 400 restaurants; this year that number is close to 1,700.

More people eat away from home

Many societal factors play into America's explosion of restaurants, explain the Zagats. First of all, says Tim, 65 percent of families include two wage-earners. By contrast, when they started the guides, only 45 percent of families fit that category. So more people have less time to shop for food and less time or energy to cook after a day at the office. Also, much of the job growth in recent years has taken place in the white-collar sector, says Tim, contributing to an increased ability to "write off meals" to Uncle Sam.

Also fueling the dining-out trend is the rise in what the Zagats refer to as "BATH" restaurants, an acronym for Better Alternative Than Home. These are restaurants that offer a casual, relaxed, and homey atmosphere with simple, fresh, and hearty food. These establishments are typically reasonably priced, adding to their attractiveness for families, who usually steer clear of more upscale, white-tablecloth restaurants.

Family dining is cultivating an early affinity for dining out among children, which is also helped along at school, says Tim, where a larger number of kids than ever are receiving free lunches or buying lunch.

The increased diversity in dining spots is a natural result of the swelling immigrant population, the growing number of chefs who are trained in a variety of cuisines, the greater accessibility of ethnic ingredients, and the sophistication of today's typical American diner, who is generally well-traveled and hence, well-versed in the flavors and dishes of various world cuisines.

Diners' demands grow

The typically more-savvy diner has also become a bit more demanding. This is perhaps a result of the recent diet craze, when the Atkins, South Beach, and other fad diets banned certain foods. While those diets are a lot less talked about these days, the lasting result has left diners feeling more empowered to ask for what they think is good for them, says Tim.

Diners are also increasingly seeking out restaurants that offer simple cooking with farm-fresh ingredients, which often jibes with what many of today's chefs are delivering. "The best chefs," says Tim, "are focusing more on cooking with organic ingredients from local farmers, who are growing specifically for them." It's not uncommon today for a restaurant to credit a nearby farm on its menu for the baby carrots or fingerling potatoes.

Today's more discerning diners are likely to welcome the Zagat redesign, as they can more easily flip through its pages in search of a particular type of restaurant. The newly revised format also features pullout maps with markings for restaurants and handy stickers ("Must Try," "My Favorite," "Love it," and several blanks for perhaps less superlative write-in comments), as well as jump-off-the-page red type for restaurant names with the type of cuisine beside them, in case there's any question.

It's a format that Tim Zagat didn't instantly warm up to. "The vote for the redesign was 109 to 1," he says, smiling. "But I came around, and now I think it's a much cleaner, fresher look."

But even more than the look, the Zagats seem thrilled about their roles in chronicling a culinary revolution that is producing more interesting choices and better quality in restaurants than ever before. And they savor opportunities that come along to help support a suffering economy, such as that of post-Katrina New Orleans, a city long celebrated for its legendary Cajun and Creole cuisine. The Zagats offered their latest New Orleans guide at a discount, which led a local company to make 25,000 copies available free of charge in an effort to boost tourism.

Back in 1979, the Zagats had no idea their little brainstorm for fellow foodies would someday be so influential. For Tim and Nina, their work seems to be about much more than enjoying meals at excellent restaurants, satisfying as that may be, especially on a rainy spring day in Boston.

How you can become a Zagat guide reviewer

The method of ranking and reviewing restaurants for the Zagat guides might seem almost too democratic to be true. Regular folks like you and me can simply log onto zagat.com and say whatever we think about a particular restaurant? Well, yes, says Tiffany Barbalato, Zagat's manager of corporate communications. But within reason, and someone trying to cheat the system – for instance, submitting 15 glowing reviews for the same American steakhouse under different names – won't get away with it.

Ms. Barbalato explains that the Zagat staff includes a team of 12 survey-research professionals who closely monitor ratings and reviews from the more than 250,000 surveyors. "We have invested time and money into various computer filters that help us find suspicious patterns of voting," says Barbalato, adding that some results are so obvious they quickly raise a red flag. For instance, "If 2,500 people are saying a restaurant is a charming new American place with soft, romantic lighting and 17 votes say only terrible things, we're going to know someone is stuffing the ballot with those 17 votes."

Catching meddlers is critical to the Zagat operation, says Barbalato. "The basis of the Zagat survey," she explains, "is that we are a trusted, reliable source for consumers, so we insist on upholding our integrity."

But the best way to trust us, she adds, is to "judge for yourself. " Turn to the review of a restaurant you know backward and forward. "Ask yourself if the words ring true, if they match up with what you think. Most of the time, you'll find they're right on," she says confidently.

Voting for the Zagat guides typically takes place during a six-to-eight-week period, during which consumers are invited to log onto zagat.com and share their opinions about the restaurants they know best. Consumers might find out about this opportunity in the food section of their local paper, on the radio, or on TV. Along with honesty and candor, humor is encouraged, and because of this, reviews are often quite entertaining.